Autonomous vehicles can sense a surrounding environment (e.g., obstacles, roadway, etc.) and navigate autonomously through the surrounding environment without human input or at least partially without human input. That is, autonomous vehicles can operate according to different levels of autonomy. For example, an autonomous vehicle can operate according to the Society of Automotive Engineers (SAE) Level 2 classification for autonomous driving. In this autonomous operating mode, an autonomous vehicle relies, at least in part, on handovers from autonomous operation to manual control by a vehicle operator when the vehicle cannot or should not autonomously operate due to various circumstances.
However, whether initiated by the vehicle or through intervention from an operator, handovers can occur without much notice. Therefore, to reliably accomplish handovers, an operator generally should maintain both readiness to act, should the autonomy disengage, and vigilance to supervise and selectively take action when the autonomy of the vehicle fails to detect a dangerous situation.
Ensuring readiness and vigilance of the operator presents various difficulties. For example, because the vehicle can operate for extended periods without manual input from the operator under level 2 autonomy, operators can stop paying attention to the environment around the vehicle and begin daydreaming, engaging in unrelated tasks, and so on. Moreover, approaches such as audible alerts can be an annoyance to the operator instead of an effective guarantor of engagement. Furthermore, approaches that require an operator to keep their hands on the steering wheel and/or to maintain their eyes forward-facing can also be ineffective since the operator may engage in the noted postures to simply satisfy the monitoring system while still daydreaming or focusing on other tasks. Consequently, the noted approaches fail to maintain both readiness and vigilance of a vehicle operator.